CN1985319B - Content usage equipment and recording media - Google Patents

Abstract

To provide a content playback device that can use content appropriately by avoiding output of content not permitted to be used according to contract information. A playback control unit 102 extracts a content name from playback control information in a playback path information table 210, and inquires of a rights management unit 108 whether content identified by the extracted content name is playable or not. If the content is judged as being unplayable, the playback control unit 102 extracts an alternative playback number from the playback control information, and extracts a content name from playback control information whose playback number matches the alternative playback number. The playback control unit 102 then instructs a decryption unit 103 and a playback unit 107 to decrypt and play back encrypted content identified by the extracted content name.

Description

Content usage equipment and recording media

technical field

The present invention relates to a content usage device capable of protecting copyrighted works, and a recording medium on which the copyrighted works are recorded.

Background technique

In recent years, recording media such as DVDs, on which copyrighted works are recorded in digital form, such as movies and music, are widely used.

The DVD standard uses playback path control based on navigation data. According to this technique, the playback path of content can be specified with navigation data. Also, the user can interactively change the playback path through the remote controller (see Japanese Patent Application Laid-Open No. H10-336568).

Meanwhile, a content delivery system (content delivery system) using DRM (Digital Rights Management) has become popular in recent years. According to DRM, a license is provided separately by encrypted content. This license includes a license key and conditions of use. The encrypted content is decrypted with the license key, and the decrypted content is played back based on usage conditions.

Consider a case where DRM is used for playback path control of a DVD on which movies are recorded. The playback device selects content through playback path control, and checks the usage conditions of the content. Here, it is assumed that use of the content is not permitted under the use conditions. If the playback device plays the content regardless of the conditions of use, the copyright of the content is violated. On the other hand, if the playback device does not play the content that meets the usage conditions, because the preset playback path is changed, some scenes of the movie will eventually be lost. This creates ambiguities or contradictions in the film's plot, which can confuse the viewer.

Contents of the invention

In order to solve the above-mentioned problems, the object of the present invention is to provide a content usage device, a content usage method, and a device capable of appropriately using combined content including a plurality of pieces of content recorded on a recording medium by avoiding output of unusable content according to protocol information. Computer program. Another object of the present invention is to provide a recording medium recording combined content.

The object can be achieved by a content using apparatus for using combined content recorded on a recording medium, the combined content including a plurality of pieces of content, the content using apparatus including: a designated acquisition unit for acquiring one of the plurality of pieces of content ; Based on the protocol information related to the use of the specified content segment, a judging unit for judging whether the specified content segment is available; a selection unit for selecting one section of a plurality of pieces of content according to the determination result of the determination unit; and a unit for outputting the selected content segment output unit.

According to this construction, the next content to be output is selected according to the availability of specified content. In this way, outputting unusable content can be avoided. This enables the user to properly use the content without being confused.

Here, if the specified content fragment is determined to be available, the selection unit may select the specified content fragment, and if the specified content fragment is determined to be unavailable, select an alternative content fragment instead of the specified content fragment, which is the same as the specified Alternative content fragments are included in the composite content corresponding to the content fragments of the .

According to this construction, if the specified content piece is not available, the composite content includes alternative content that replaces the output of the specified content piece. This makes it possible to reliably select alternative content.

Here, the combined content recorded on the recording medium may include a content identifier for identifying a specified content piece and an alternative content identifier for identifying an alternative content piece corresponding to each other, wherein if the specified content piece is judged as available, the selection unit selects the specified content segment by extracting the content identifier from the combined content; The identifier is used to select the replaceable content piece, and the output unit reads the content piece identified by the extracted content identifier or the replaceable content identifier from the recording medium, and outputs the read content piece.

According to this configuration, alternative content can be reliably selected using the alternative content identifier.

Here, the judging unit may acquire protocol information, and judge whether the specified content segment is available based on the acquired protocol information.

According to this configuration, the availability of specified content is judged with reference to the acquired protocol information. This makes it possible to properly use the content without infringing its copyright.

Here, the combined content recorded on the recording medium may include a license identifier for identifying protocol information, wherein the judging unit includes: a protocol information storage unit for pre-storing license identifiers and protocol information corresponding to each other; An identifier extracting unit for extracting a license identifier from the combined content; and for reading protocol information corresponding to the extracted license identifier from the protocol information storage unit, and judging whether the specified content piece is based on the read protocol information Available Judgment Units.

Here, the combined content recorded on the recording medium may include a content identifier for identifying a specified content piece and a license identifier for identifying protocol information corresponding to each other, wherein the judging unit includes: for pre-storing the license identifiers corresponding to each other and a protocol information storage unit for protocol information; an identifier extracting unit for extracting a license identifier corresponding to a content identifier identifying a specified piece of content from the combined content; and for reading from the protocol information storage unit and A judging unit that extracts the protocol information corresponding to the license identifier and judges whether the specified content segment is available based on the read protocol information.

Here, the combined content recorded on the recording medium includes a content identifier for identifying a specified piece of content, wherein the judging unit includes: a protocol information storage unit for pre-storing content identifiers and protocol information corresponding to each other; an identifier extraction unit for extracting a content identifier; and a judgment for reading protocol information corresponding to the extracted content identifier from the protocol storage unit, and judging whether a specified content segment is available based on the read protocol information unit.

According to these configurations, protocol information corresponding to specified content can be reliably acquired.

Here, the combined content recorded on the recording medium may include playback path information representing a correspondence relationship between a specified content piece and a previous content piece output just before the specified content piece, wherein after the output unit outputs the previous content piece, the acquisition unit Playback path information is extracted from the combined content, and designations are obtained based on the extracted playback path information.

According to this configuration, output of unusable content can be avoided in playback path control.

Here, the plurality of pieces of content may include multiple angle content segments for multi-angle switching, wherein the acquisition unit acquires designation of one of the plurality of angle content segments. The judging unit judges whether the specified angle content fragment is available based on the protocol information, and the selection unit selects a group of outputtable angle content fragments according to the judgment result generated by the judging unit, and selects an angle content fragment from the selected group, and outputs The unit outputs the selected angular content fragment.

According to this configuration, when multi-angle switching is controlled, output of unusable content can be avoided.

Here, the pieces of content may include multiple pieces of auxiliary content, and each piece of auxiliary content may be composed of any audio data and subtitle data output together with the video data, wherein the acquisition unit acquires a specified one of the plurality of auxiliary content. The judging unit judges whether the specified auxiliary content fragment is available based on the protocol information, the selecting unit selects a group of outputtable auxiliary content fragments according to the judgment result of the judging unit, and selects an auxiliary content fragment from the selected group, and outputs The cell outputs the selected auxiliary content fragment.

According to this configuration, when controlling playback of audio or subtitle data accompanying video data, output of unusable content can be avoided.

Here, each piece of content may include an encrypted digital work, wherein the output unit decrypts the encrypted digital work included in the selected piece of content and outputs the decrypted digital work.

According to this configuration, the content usage device decrypts the encrypted digital work in the combined content recorded on the recording medium, and outputs the decrypted digital work. Therefore, even if the combined content is copied to another recording medium without authorization, the digital works in the copied combined content cannot be used without authorization.

Also, the object can be achieved by a recording medium on which combined content comprising a plurality of pieces of content is recorded, wherein the combined content comprises content pieces corresponding to each other and alternative content pieces, if the content pieces are not available, then output the replaceable content fragment instead of the content fragment.

According to this configuration, when the above-mentioned content using device uses the recording medium, it is possible to avoid outputting unusable content.

Brief description of the drawings

Fig. 1 has shown the overall construction as the content playback system of the embodiment of the present invention;

Fig. 2 shows the internal structure of the playback device and the information stored on the recording medium shown in Fig. 1;

FIG. 3 shows an example data structure of a playback path information table stored on a recording medium;

Figure 4 shows an example of video playback when using the playback path information table shown in Figure 3;

FIG. 5 shows an example data structure of a button data table stored on a recording medium;

FIG. 6 shows an example of video playback including a plurality of buttons when the button data table shown in FIG. 5 is used.

FIG. 7 shows another example of video playback including a plurality of buttons when the button data table shown in FIG. 5 is used.

Fig. 8 shows an example data structure of a key control information table stored on a recording medium.

FIG. 9 shows an example data structure of a media information table stored on a recording medium.

Fig. 10 shows an example data structure of the copyright information table stored in the copyright storage unit of the playback device.

Fig. 11 shows the internal configuration of the license server device shown in Fig. 1 .

Fig. 12 is a flowchart of the content playback start operation of the playback device.

Fig. 13 is a flowchart of a media key generation operation performed by a media key generation unit in the playback device.

Fig. 14 is a flowchart of a content playback control operation by a playback control unit in the playback device.

Fig. 15 is a flowchart of content decryption and playback operations performed by a decryption unit and a playback unit in the playback device.

Fig. 16 is a flowchart of a content key acquisition operation by a key control unit in the playback device.

Fig. 17 is a flowchart of a copyright key acquisition operation performed by a copyright management unit in the playback device.

Fig. 18 is a flowchart of a playability judging operation by a key control unit in the playback device.

Fig. 19 is a flowchart of a playability judging operation by a copyright management unit in the playback device.

Fig. 20 is a flowchart of an operation performed by the playback device to acquire copyright information from the license server device.

Fig. 21 shows the overall configuration of a content recording/playback system as a modification of this embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

The content playback system 1 as an embodiment of the present invention is described below.

1.1 Construction of content playback system 1

FIG. 1 shows the configuration of a content playback system 1 . As shown in the figure, this content playback system 1 roughly includes a playback device 100 and a license server device 300 connected via the Internet 10 . A display device 113 such as a television monitor is connected to the playback device 100 . Meanwhile, the user loads a recording medium 200 such as a BD into the playback device 100 . The playback device 100 receives operations from the user through the remote controller 112 . According to the received operation, the playback device 100 plays back the content recorded on the recording medium 200, or acquires copyright information on the content from the license server device 300 and retains the acquired copyright information.

1.2 Structure of recording medium 200

FIG. 2 shows information stored on the recording medium 200 . As explained, the recording medium 200 prestores the playback path information table 210 , encrypted contents 231 , 232 , . . . , 238 , key control information table 260 and medium information table 280 . The playback path information table 210, the encrypted contents 231, 232, . . . , 238, the key control information table 260, and the media information table 280 constitute combined contents (composite contents). The combined content referred to here is a content type that includes a combination of different content pieces.

(1) Playback path information table 210

FIG. 3 shows an example of the playback path information table 210 . In this figure, the playback path information table 210 includes eight groups of playback control information 291, 292, . . . one. These eight sets of playback control information 291 , 292 , . Each set of playback control information includes a playback number, a content name, a next playback number, and an alternative playback number. Here, the playback control information may not include an alternative playback number, and may also not include a next playback number.

(replay number)

The playback number included in the playback control information is an index number for uniquely identifying the playback control information. The playback number starts from 1 and increases by 1 for each set of playback control information. For example, the playback control information 291 has a playback number 212 "1", which uniquely identifies the playback control information 291 . At the same time, the playback control information 292 includes a playback number 217 "2", which uniquely identifies the playback control information 292 .

(content name)

The content name included in the playback control information identifies encrypted content corresponding to the playback control information. As an example, the content name is a file name that uniquely identifies encrypted content recorded on the recording medium 200 as one file.

(next replay number)

When the decryption and playback of the encrypted content corresponding to the previous playback control information are completed, the next playback number included in the playback control information specifies the playback corresponding to the encrypted content to be decrypted and then played. control information. If there is no encrypted content to be decrypted and then played, a replay number is not set.

For example, playback control information 291 has next playback number 214 "2". Therefore, after the decryption and playback of the encrypted content identified by the content name 213 "Opening. The encrypted content identified by the content name 218 "Trailer.mpg" is decrypted and played.

(replaceable replay number)

If the decryption and playback of the encrypted content specified by the next playback number is not allowed, the alternative playback number included in the playback control information specifies the encryption content corresponding to the alternatively to be decrypted and played playback control information.

For example, playback control information 292 has a next playback number 219 "3" and an alternate playback number 220 "4". Assume that decryption and playback of the encrypted content corresponding to the playback control information 293 designated by the next playback number 219 "3", that is, the encrypted content identified by the content name 221 "Movie.mpg", is not permitted. In this case, after decryption and playback of the encrypted content identified by the content name 218 "Trailer. The corresponding encrypted content is the encrypted content identified by the content name 222 "Waming.mpg".

If the playback control information does not include an alternative playback number, the encrypted content designated by the next playback number is decrypted and played back regardless of whether the encrypted content is playable or not.

(replay example)

FIG. 4 shows a playback example when using the playback path information table 210 shown in FIG. 3 .

As shown in FIG. 4 , video 401 is played first, and then video 402 is played. Thereafter, video 403 is played if it is playable, and then video 405 is played. If video 403 is not playable, video 404 is played instead. At the same time, the videos 406, 407 and 408 are played according to the conditions.

Here, videos 401, 402, . . . , 408 respectively correspond to playback control information 291, 292, . . . , 298 shown in FIG. 3 .

(2) encrypted content 231, 232, ..., 238

Each encrypted content 231 , 232 , . . . , 238 constitutes a file on the recording medium 200 .

The encrypted contents 231, 232, . . . , 238 have the same data structure. That is, the encrypted content is obtained by applying an encryption algorithm to the payload in each packet of the transport stream except for the adaptation field, by multiplexing according to the MPEG-2 multiplexing system MPEG-2 video elementary stream and MPEG-2 audio elementary stream to generate the transport stream. As an example, the encryption algorithm referred to here is AES (Advanced Encryption Standard), although other key encryption algorithms may also be applied.

(button data sheet 240)

If the encrypted content is menu display content, the encrypted content includes, in encrypted form, a button data table 240 that displays buttons as a private stream, in addition to video elementary streams and audio elementary streams. It should be noted that the way of including the encryption button data table is not limited to this.

FIG. 5 shows an example of the button data table 240 . In this figure, the button data table 240 includes four groups of button data, which respectively correspond to the four buttons 422, 423, 424 and 425 in the menu display 421 shown in FIG. 6, and also respectively correspond to the menu display 431 shown in FIG. The four buttons 432, 433, 434 and 435 in . Each set of button data includes button number, playback number, up button number, down button number, left button number, right button number, unselected data, selected data and grayed-out data. Here, button data may not include grayed out data.

(a) Button number

The button number included in the button data is an index number for uniquely identifying the button data. The button number starts from 1 and increases by 1 for each set of button data. When the playback of the menu display content is started, the button corresponding to the button data identified by the button number 241 "1" is put into the selected state.

(b) Replay number

When it is determined that a button corresponding to the button data is selected by the remote controller 112, the playback number included in the button data identifies playback control information corresponding to the encrypted content to be played.

For example, button data identified by button number 241 "1" has playback number 242 "2". Therefore, when the button corresponding to the button data is in the selected state and the confirmation operation is carried out by the remote controller 112, the program with the playback number 217 "2" in the playback path information table 210 in Fig. 3 is decrypted and played. The encrypted content corresponding to the playback control information 292 of ", that is, the encrypted content identified by the content name 218 "Trailer.mpg".

(c) Up button number

When an upward movement operation is performed by the remote controller 112 while the button corresponding to the previous button data is in the selected state, the up button number included in the button data identifies the button data corresponding to the button entering the selected state.

For example, button data identified by button number 241 "1" has an up button number 243 "4". In this way, if the button corresponding to the button data is in the selected state and the remote controller 112 performs an upward movement operation, then the button corresponding to the button data identified by the up button number 243 "4" enters the selected state.

(d) Down Button No.

When the button corresponding to the previous button data is in the selected state while the down move operation is performed by the remote controller 112, the down button number included in the button data identifies the button data corresponding to the button that entered the selected state .

(e) Left button number

When a left movement operation is performed by the remote controller 112 while the button corresponding to the previous button data is in the selected state, the left button number included in the button data identifies the button data corresponding to the button that entered the selected state.

(f) Right button number

When a right shift operation is performed by the remote controller 112 while the button corresponding to the previous button data is in the selected state, the right button number included in the button data identifies the button data corresponding to the button entering the selected state.

(g) Unselected data

The unselected data included in this button data is image data representing a button to be displayed when the button is in an unselected state.

(h) Selected data

The selected data included in this button data is image data representing a button to be displayed when the button is in a selected state.

(i) Grayed out data

The grayed out data included in the button data is image data representing a button to be displayed when the button is in a grayed out state, that is, a non-selectable state. For example, the image data is generated by replacing replaceable pixels of unselected data with empty pixels. Such image data is less clear than non-selected data, thereby indicating that the button cannot be selected. The grayed out state is explained in more detail later.

(3) Key control information table 260

FIG. 8 shows an example of the key control information table 260 . As shown, the key control information table 260 includes multiple sets of key control information, and each set of information corresponds to any encrypted content 231 , 232 , . . . , 238 recorded on the recording medium 200 . Each set of key control information includes content name, content information, key generation information, playability information, copyability information, and copyright mode information.

(content name)

The content name included in the key control information identifies the encrypted content corresponding to the key control information. Similar to the content name in the playback path information table 210 shown in FIG. 3, the content name in the key control information table 260 indicates a file name identifying the corresponding encrypted content. However, unlike the playback path information table 210, the same content name never appears in the key control information table 260 more than once.

(content information)

The content information included in the key control information is used to generate a content key for decrypting encrypted content corresponding to the key control information. The content information is unique to the corresponding encrypted content.

(key generation information)

The key generation information included in the key control information specifies a method of generating a content key for encrypted content corresponding to the key control information. The key generation information takes one of values "00", "01" and "10". A value of "00" indicates that the media key will be used to generate the content key. A value of "01" indicates that the combined key will be used to generate the content key. A value of "10" indicates that a copyright key (also called a license key) will be used to generate a content key. The media key, composite key, and copyright key are explained in detail later.

(playability information)

The playability information included in the key control information indicates whether the encrypted content corresponding to the key control information is playable. The playability information takes one of values "1" and "0". A value of "1" indicates that the encrypted content is playable. A value of "0" indicates that the encrypted content is not playable.

Although in this example, the playability information indicates whether the encrypted content is playable, this is not a limitation of the present invention. For example, the playability information may indicate playback quality, such that if the playability information indicates high playback quality, the encrypted content is judged to be unplayable, and if the playability information indicates low playback quality, it is judged to be playable.

(copyability information)

The copyability information included in the key control information indicates whether the encrypted content corresponding to the key control information can be copied. The copyability information takes one of values "01", "10" and "00". The value "01" means "once", that is, the content can be copied once. The value "10" means "free", that is, the content can be freely copied. The value "00" means "never", that is, the content is never allowed to be copied.

Although in this example, any one of "once", "freely" and "never" is shown, the present invention is not limited thereto. For example, the copyability information may indicate copy quality. Meanwhile, the copyability information may contain information for specifying a copy destination medium.

(copyright mode information)

When the key generation information in the key control information is "10" (copyright key) or "01" (combined key), the copyright mode information included in the key control information is designated as corresponding to the key control information One or more copyright modes specified by the encrypted content. For example, when the copyright mode information is "01", mode A is designated for the content. When the content mode information is "10", mode B is designated for the content. When the copyright mode information is "01, 10", modes A and B are specified for the content.

The copyright model mentioned here is a model for generating copyright for content. As an example, Mode A generates rights based on the maximum number of times the content is allowed to be played back, while Mode B generates rights based on an expiration date, allowing playback of the content until that date.

When the key generation information in the key control information is "00" (media key), the copyright mode information in the key control information is "00", indicating that no copyright mode is specified.

For example, the copyright mode information 266 in FIG. 8 is "00", which means that the copyright mode is not specified for the content corresponding to the key control information including the copyright mode information 266 .

Meanwhile, the copyright mode information 272 is "01", which means that mode A is specified for the content corresponding to the key control information including the copyright mode information 272 . Therefore, only the copyright generated in mode A is used as the copyright to use the content.

Meanwhile, the copyright mode information 273 is "01, 10", which means that modes A and B are specified for the content corresponding to the key control information including the copyright mode information 273 . Therefore, the copyright generated in either of modes A and B is used as the copyright to use the content.

Also, the copyright mode information 274 is "10", which means that mode B is specified for the content corresponding to the key control information including the copyright mode information 274 . Therefore, only the copyright generated in mode B is used as the copyright to use the content.

(4) Media information table 280

FIG. 9 shows an example of the media information table 280 . As shown, the media information table 280 includes multiple sets of media information, each set of media information corresponding to an individual playback device. Each set of media information includes device information and an encrypted media key.

(Device Information)

The device information included in the media information is uniquely given to the playback device corresponding to the media information.

(encrypted media key)

An encrypted media key included in the media information is generated by applying an encryption algorithm to the media key using a unique device key of the playback device corresponding to the media information. As an example, the encryption algorithm referred to here is AES, although other key encryption algorithms are equally available. This media key is uniquely assigned to the recording medium 200 .

Thus, the media information table 280 includes encrypted media keys generated for individual playback devices. It is assumed that a playback device becomes unauthorized as a result of hacking or the like. In this case, in subsequent production of recording media, a media information table that does not include media information corresponding to unauthorized playback devices is generated and written into each recording medium. By doing so, content playback by unauthorized devices can be prevented.

In this embodiment, as many media information groups as playback devices are stored in the media information table 280 . This unnecessarily increases the data size of the media information table 280 . To avoid this, a binary tree can be used to reduce the data size of the media information table 280 .

1.3 Construction of playback device 100

FIG. 2 also shows the configuration of the playback device 100 . In this figure, a playback device 100 includes a drive unit 101, a playback control unit 102, a decryption unit 103, a key control unit 104, a media key generation unit 105, a reception unit 106, a playback unit 107, a copyright management unit 108 , a copyright storage unit 109 , a communication unit 110 , a device information storage unit 111 , and a power supply unit (not shown) that supplies power to each constituent element of the playback device 100 .

The playback device 100 is actually realized by a computer system roughly composed of a CPU, work memory, flash memory, BD drive, video adapter, network adapter, and the like. The drive unit 101 is realized by BD drive. The receiving unit 106 receives operations from the remote controller 112 through infrared signals. The playback unit 107 is realized by a video adapter. The copyright storage unit 109 and the device information storage unit 111 are realized by flash memory. The communication unit 110 is realized by a network adapter. Meanwhile, the flash memory also stores a plurality of computer programs representing the operations of the playback control unit 102 , the decryption unit 103 , the key control unit 104 , the media key generation unit 105 , and the copyright management unit 108 . The functions of the playback control unit 102, the decryption unit 103, the key control unit 104, the media key generation unit 105, and the copyright management unit 108 are accomplished by the CPU operating in accordance with corresponding computer programs.

(1) Device information storage unit 111 and copyright storage unit 109

(device information storage unit 111)

The device information storage unit 111 pre-stores device information 141 and a device key 142 , as shown in FIG. 2 .

The device information 141 is uniquely provided to the playback device 100 . The device key 142 is uniquely provided to the playback device 100 .

(copyright storage unit 109)

The copyright storage unit 109 stores a copyright information table 121 in advance, as shown in FIG. 2 .

FIG. 10 shows an example of the copyright information table 121 . In the figure, copyright information table 121 includes multiple sets of copyright information, each set of copyright information corresponding to any one of encrypted contents 231, 232, . . .

Each set of copyright information is composed of copyright mode information, content name, copyright key, playback count, and playback effective date. Here, the copyright information may not include a replay count or a replay valid date.

The copyright mode information included in the copyright information indicates the copyright mode specified for the encrypted content corresponding to the copyright information. This copyright model represents a method of generating copyright for content use.

The content name included in the copyright information identifies the encrypted content corresponding to the copyright information. Like the content names included in the playback path information table 210 shown in FIG. 3, the content names in the copyright information table 121 are file names that uniquely identify the corresponding content.

The copyright key included in the copyright information is key information provided to the copyright indicated by the copyright information.

The playback count included in the copyright information is the maximum number of times the corresponding content is allowed to be played back. The absence of a replay count in the copyright information means that the content can be replayed an unlimited number of times.

The playback valid date included in the copyright information indicates the valid date when playback of the corresponding content is permitted all the time. The lack of a playback expiration date in the copyright information means that there is no time limit on playback of this content.

Although copyright information is composed of five items, ie, copyright mode information, content name, copyright key, playback count, and playback effective date in the above example, the present invention is not limited thereto. For example, copyright information may include other items such as playback device restrictions, user restrictions, and geographic region restrictions.

(2) Playback control unit 102

The playback control unit 102 receives an instruction to play back the content recorded on the recording medium 200 from the receiving unit 106 . The playback control unit 102 also receives a detection signal indicating insertion of the recording medium 200 from the drive unit 101 .

When the playback instruction is received from the receiving unit 106 or the detection signal is received from the drive unit 101 immediately after receiving power from the power supply unit, the playback control unit 102 outputs an instruction to decrypt the content recorded on the recording medium 200 to the decryption unit. 103.

Thereafter, the playback control unit 102 receives from the decryption unit 103 a decryption failure notification indicating that content decryption has failed or a media key acquisition success notification indicating that media key acquisition has succeeded. When receiving the decryption failure notification, the playback control unit 102 terminates subsequent playback control operations. When receiving the media key acquisition success notification, the playback control unit 102 performs the playback control operation described below.

(Playback control operation)

The playback control unit 102 causes the drive unit 101 to read the playback control information having the playback number “1” from the playback path information table 210 on the recording medium 200 . The playback control unit 102 extracts the content name from the read playback control information, and outputs the extracted content name to the decryption unit 103 . The playback control unit 102 instructs the decryption unit 103 to decrypt and play the encrypted content identified by the content name.

Once the encrypted content identified by the content name has been decrypted and played back, the playback control unit 102 attempts to extract the next playback number from the playback control information. If there is no next playback number in the playback control information, the playback control unit 102 ends the playback control operation.

If there is a next playback number in the playback control information, the playback control unit 102 causes the drive unit 101 to read the playback number whose playback number matches the next playback number extracted from the playback path information table 210. control information. Then, the playback control unit 102 extracts the content name from the read playback control information, and outputs the extracted content name to the copyright management unit 108 through the decryption unit 103 and the key control unit 104 . The playback control unit 102 queries the copyright management unit 108 through the decryption unit 103 and the key control unit 104 whether the encrypted content identified by the content name is playable.

If the copyright management unit 108 replies that the content is not playable, the playback control unit 102 extracts an alternative playback number from the playback control information. The playback control unit 102 causes the drive unit 101 to read playback control information whose playback number matches the alternative playback number extracted from the playback path information table 210 . The playback control unit 102 then extracts the content name from the read playback control information, outputs the extracted content name to the decryption unit 103, and instructs the decrypted content 103 to decrypt and play the encrypted content identified by the content name. Once the decryption and playback of the encrypted content is completed, the playback control unit 102 attempts to extract the next playback number from the playback control information. If no next playback number is included in the playback control information, the playback control unit 102 ends the playback control operation.

On the other hand, if copyright management unit 108 replies that the content can be played, playback control unit 102 outputs the content name to decryption unit 103 and instructs decryption unit 103 to decrypt and play the encrypted content identified by the content name. Once the decryption and playback of the encrypted content is completed, the playback control unit 102 attempts to extract the next playback number from the playback control information. If the playback control information has no next playback number, the playback control unit 102 ends the playback control operation.

If the playback control information has a next playback number, the playback control unit 102 repeats the above operations until the next playback number cannot be extracted.

(3) Decryption unit 103, playback unit 107, and display unit 113

(decryption unit 103)

The decryption unit 103 receives an instruction to decrypt the content recorded on the recording medium 200 from the playback control unit 102 , and outputs an instruction to acquire a media key to the key control unit 104 .

Thereafter, the decryption unit 103 receives from the key control unit 104 a media key acquisition failure notice indicating a media key acquisition failure or a media key acquisition success notice indicating a media key acquisition success. When receiving the media key acquisition failure notification, the decryption unit 103 outputs a decryption failure notification indicating that content decryption has failed to the playback control unit 102 . Upon receiving the media key acquisition success notification, the decryption unit 103 outputs the media key acquisition success notification to the playback control unit 102 .

Then, the decryption unit 103 receives a file name and an instruction to decrypt the encrypted content identified by the content name from the playback control unit 102 . The decryption unit 103 causes the key control unit 104 to acquire the content key corresponding to the encrypted content, and causes the drive unit 101 to read the encrypted content from the recording medium 200 .

If the decryption unit 103 receives from the key control unit 104 the content key acquisition failure notification indicating that the content key acquisition has failed, the decryption unit 103 outputs the decryption failure notification indicating that the content decryption has failed to the playback control unit 102, and terminates the subsequent operate.

Next, the decryption unit 103 judges whether the read encrypted content contains an encrypted button data table. Although this is not limiting to the present invention, this determination can be made by referring to the unencrypted PAT (Program Association Table) or PMT (Program Mapping Table) in the encrypted content to check whether the encrypted content includes a private stream.

(a) If the encrypted content does not contain an encrypted button data table, the decryption unit 103 decrypts the encrypted content with the content key in units of packets, and outputs the decrypted content to the playback unit 107 .

(b) If the encryption unit includes an encrypted button data table, the decryption unit 103 decrypts the encrypted button data with the content key, and performs the following processes (i) to (iv) on each group of button data in the decrypted button data table .

(i) The decryption unit 103 extracts the playback number from the button data.

(ii) The decryption unit 103 acquires the content name corresponding to the extracted playback number from the playback path information table 210 through the drive unit 101 . In detail, the decryption unit 103 causes the drive unit 101 to read the playback control information whose playback number matches the extracted playback number from the playback path information table 210 on the recording medium 200, and The content name is extracted from the control information.

(iii) The decryption unit 103 outputs the content name to the copyright management unit 108 through the key control unit 104, and queries the copyright management unit 108 through the key control unit 104 whether the content identified by the content name is playable.

(iv) If the copyright management unit 108 replies that the content can be played, the decryption unit 103 extracts unselected data and selected data representing normal button display from the button data. If the copyright management unit 108 replies that the content cannot be played, the decryption unit 103 extracts grayed out data representing grayed out button display from the button data. This completes processes (i) to (iv).

Then, the decryption unit 103 decrypts the encrypted content with the content key in units of packets, and outputs the decrypted content to the playback unit 107 .

The decryption unit 103 also outputs the selected data and unselected data or grayed out data extracted for each set of button data to the playback unit 107 .

(playback unit 107)

The playback unit 107 receives the decrypted content from the decryption unit 103, and decodes it to generate digital video and audio data. The playback unit 107 generates analog video and audio signals from digital video and audio data, and outputs the analog video and audio signals to the display device 113 .

At the same time, the playback unit 107 receives selected data and unselected data or grayed out data extracted for each set of button data from the decryption unit 103, and superimposes the selected data and unselected data or grayed out data on the video data so that each button is displayed. In this way, the display state of each button changes according to the playability of the content corresponding to that button. That is, display the button in a normal state if the content is playable, and display the button in a grayed out state if the content is not playable. When a button is grayed out, it is not possible to confirm the selection of the button.

(display device 113)

The display device 113 receives analog video and audio signals from the playback unit 107, and outputs the video signal as video and the audio signal as sound.

(4) Key control unit 104

Key control unit 104 receives an instruction to acquire a media key from decryption unit 103 , and outputs an instruction to generate a media key to media key generation unit 105 .

Thereafter, the key control unit 104 receives from the media key generation unit 105 the decrypted media key or a media key generation failure notification indicating that the media key generation failed.

When receiving the media key generation failure notice, the key control unit 104 outputs a media key acquisition failure notice indicating that the media key acquisition has failed to the decryption unit 103 .

When receiving the decrypted media key, the key control unit 104 outputs a media key acquisition success notification indicating that the media key acquisition was successful to the decryption unit 103 .

(Content key acquisition)

Then, the key control unit 104 acquires the content key in the following manner according to an instruction from the decryption unit 103 .

The key control unit 104 receives a content name and a content key acquisition instruction from the decryption unit 103 . The key control unit 104 causes the drive unit 101 to read the key control information containing the received content name from the key control information table 260 on the recording medium 200, and extract the key generation key from the read key control information. information.

The key control unit 104 judges whether the key generation information is "00" indicating "media key". If the key generation information is "00", the key control unit 104 extracts the content information from the key control information, and concatenates the decrypted media key received from the media key generation unit 105 and the extracted content information in this order stand up. Then, the key control unit 104 applies a one-way function to the concatenation result, thereby generating a content key. As an example, the one-way function referred to here is SHA-1.

(Content Key)=SHA-1((Decrypted Media Key)||(Content Information))

Here, "SHA-1(x)" represents a hash value (hash value) obtained by SHA-1 transforming X, and "A||B" represents the result of concatenating A and B in this order.

It should be noted here that the generation of the content key is not limited to the above. For example, other hash functions or one-way functions could be used. Alternatively, the content key may be generated by decrypting the content information with the decrypted media key.

The key control unit 104 outputs the generated content key to the decryption unit 103 .

If the key generation information is not “00”, the key control unit 104 extracts the copyright mode information from the key control information, and outputs the content name and the copyright mode information to the copyright management unit 108 . The key control unit 104 controls the copyright management unit 108 to acquire a copyright key corresponding to the content identified by the content name. If the key control unit 104 receives the copyright key acquisition failure notice indicating that the copyright key acquisition has failed from the copyright management unit 108, the key control unit 104 outputs the content key acquisition failure notice indicating that the content key acquisition has failed to the decryption unit 103, and end the follow-up operation.

Next, the key control unit 104 judges whether the key generation information is "01" or "10". If the key generation information is “10” indicating “copyright key”, key control unit 104 sets the acquired copyright key as the content key, and outputs the content key to decryption unit 103 .

Although the copyright key itself is set as the content key if the key generation information indicates "copyright key" in the above example, the present invention is not limited to this. For example, a one-way function can be used to generate a content key from a copyright key and content information. Also, the generation of the content key from the copyright key may be performed not by the key control unit 104 but by the copyright management unit 108 . This especially enhances security when the key control unit 104 and the copyright management unit 108 are implemented as separate tamper-resistant modules, since the copyright key does not need to be output to the key control unit 104 .

If the key generation information is "01" representing "combined key", the key control unit 104 concatenates the decrypted media key and the acquired copyright key in this order, and performs a one-way function on the concatenated result to obtain Generate a content key.

(Content Key)=SHA-1((Decrypted Media Key)||(Copyright Key))

Key control unit 104 outputs the generated content key to decryption unit 103 .

Note that the generation of content keys here is not limited to the use of one-way functions. For example, the content key may be generated by decrypting the content information with the decrypted media key, or by decrypting the copyright key in encrypted form with the decrypted media key. The content information can be used in the generation of the content key. Especially when the key control unit 104 and the copyright management unit 108 are implemented as a separate anti-tampering module, the key control unit 104 can generate information from the decrypted media key and content information and inform the copyright management unit 108, The copyright management unit then generates a content key from the notified information and the copyright key. This makes it unnecessary to output the decrypted media key to the copyright management unit 108 and the copyright key to the key control unit 104, thus contributing to higher security.

(Content Playability Judgment)

When the playability judgment of the content is required during the playback control operation, the key control unit 104 reads the key control information corresponding to the content from the recording medium 200, and judges the playability of the content as follows.

The key control unit 104 receives the content name and an instruction to judge the playability of the content identified by the content name from the decryption unit 103 . In response, the key control unit 104 causes the drive unit 101 to read the key control information having the received content name from the key control information table 260 on the recording medium 200, and extract the key control information from the read key control information. key to generate information.

The key control unit 104 judges whether the key generation information is "00" indicating "media key". The key control unit 104 extracts the playability information from the key control information, and judges whether the playability information is "0" or "1". If the playability information is "1", the key control unit 104 outputs a playback permission notification indicating that the content is playable to the decryption unit 103 . If the playable information is "0", the key control unit 104 outputs playback prohibition information indicating that the content is not playable to the decryption unit 103 .

If the key generation information is not "00", the key control unit 104 extracts the playability information from the key control information, and judges whether the playability information is "0" or "1". If the playability information is “1”, the key control unit 104 outputs a playback permission notification to the decryption unit 103 . If the playability information is “0”, the key control unit 104 extracts the copyright mode information from the key control information, and outputs the copyright mode information, content name and copyright judgment instruction to the copyright management unit 108 . Then, the key control unit 104 receives the judgment result on the content playability from the copyright management unit 108 and outputs the judgment result to the decryption unit 103 .

In the case where the key generation information is not "00", even when the content is judged to be playable, the content key cannot be obtained, so unless the copyright management unit 108 obtains the copyright key, the content key cannot be decrypted and played. content. To avoid any confusion arising from this, it is preferable to determine that the content is playable after confirming the presence of the copyright key, rather than simply determining that the content is playable based on the playability information.

(5) Media key generation unit 105

The media key generation unit 105 receives a media key generation instruction from the key control unit 104 . In response, the media key generation unit 105 reads the device information 141 from the device information storage unit 111 . The media key generation unit 105 causes the drive unit 101 to read the media information from the media information table 280 on the recording medium 200, and extract the device information from the read media information. The media key generation unit 105 compares the extracted device information with the device information 141 .

If the extracted device information does not match the device information 141, the media key generation unit 105 repeats the reading of the next media information from the media information table 280, extracts the device information from the read media information, and compares until Each set of media information is read from the media information table 280 .

If the same device information as device information 141 is not found in media information table 280 , media key generation unit 105 outputs a media key generation failure notification indicating media key generation failure to key control unit 104 .

On the other hand, if the extracted device information matches the device information 141, the media key generation unit 105 reads the device key 142 from the device information storage unit 111, and extracts the encrypted media key from the read media information . The media key generation unit 105 decrypts the encrypted media key using the device key 142 according to AES, and outputs the decrypted media key to the key control unit 104 .

(6) Copyright management unit 108

(Copyright key acquisition)

The copyright management unit 108 receives the content name and copyright mode information from the key control unit 104 . The copyright management unit 108 judges whether the copyright mode information is "00", "01", "10" or "01, 10" to determine whether any copyright mode is specified for the content identified by the content name.

If the copyright mode is specified for the content, that is, if the copyright mode information is "01", "10" or "01,10", the copyright management unit 108 attempts to extract the copyright information from the copyright information table 121 in the copyright storage unit 109. Copyright information including the received copyright mode information and content name.

In more detail, if the copyright mode information is "01", the copyright management unit 108 attempts to extract copyright information containing the copyright mode information "01" and the content name. If the copyright mode information is "10", the copyright management unit 108 attempts to extract copyright information including the copyright mode information "10" and the content name. If the copyright mode information is "01, 10", the copyright management unit 108 tries to extract the copyright information including the copyright mode information "01" and the content name, and the copyright information including the copyright mode information "10" and the content name.

Assume that the copyright mode information specifies mode A, and the content name is "Making.mpg". In this case, copyright information 132 is extracted from copyright information table 121 shown in FIG. 10 instead of copyright information 133 . Assume that the copyright mode information specifies modes A and B, and the content name is "Making.mpg". In this case, the copyright information 132 and the copyright information 133 are extracted from the copyright information table 121 .

If the copyright mode is not specified for the content, that is, if the copyright mode information is "00", the copyright management unit 108 attempts to extract the copyright information including the content name from the copyright information table 121 .

For example, if the copyright mode information does not specify a copyright mode, and the content name is "Movie.mpg", the copyright information 131 is extracted from the copyright information table 121 shown in FIG. 10 .

As a result, at least one set of copyright information is extracted, or no set of copyright information is extracted at all.

In this embodiment, after judging the playability of the content, playback of the content is commanded. Therefore, failure to extract copyright information means that some kind of problem such as an unauthorized attack has occurred.

If multiple sets of copyright information are extracted, the copyright management unit 108 selects one of the sets of copyright information. If a set of copyright information is extracted, the copyright management unit 108 selects the copyright information. Then, the copyright management unit 108 judges whether or not the content identified by the content name is playable using the playback count and/or playback effective date included in the selected copyright information.

When the replay count is used, the copyright management unit 108 judges the content as playable if the replay count is not "0" and as unplayable if the replay count is "0".

When using the playback valid date, if the clock installed in the copyright management unit 108 shows that the current time is within the playback valid date, the copyright management unit 108 judges that the content is playable; if the current time exceeds the playback valid date, Then it is judged that the content is unplayable.

When using playback count and playback effective date simultaneously, if the above two judgments are positive, the copyright management unit 108 judges that the content is playable, if any one of the above two judgments is negative, then it is judged as Not playable.

If the content is judged to be playable, the copyright management unit 108 extracts the copyright key from the selected copyright information, and outputs the copyright key to the key control unit 104 .

If the content is judged not to be playable, it means that copyright key acquisition has failed, in which case the copyright information set is not extracted. When this happens, the copyright management unit 108 outputs to the key control unit 104 a copyright key acquisition failure notification indicating that the copyright key acquisition has failed.

(Content Playability Judgment)

The copyright management unit 108 receives the copyright judgment instruction, content name and copyright mode information from the key control unit 104 . Then, the copyright management unit 108 judges whether the copyright mode information is "00", "01", "10" or "01,10" to judge whether any copyright mode is specified for the content identified by the content name in the same manner as above.

If the copyright mode is specified for the content, the copyright management unit 108 attempts to extract the copyright information including the received copyright mode information and the content name from the copyright information table 121 of the copyright storage unit 109 in the same manner as above.

If the copyright mode is not specified for the content, the copyright management unit 108 attempts to extract the copyright information including the received content name from the copyright information table 121 in the same manner as described above.

As a result, at least one set of copyright information is extracted, or no set of copyright information is extracted.

If at least one set of copyright information is extracted, the copyright management unit 108 selects a set of copyright information, and judges whether the content is available in the same manner as described above based on the playback count and/or playback effective date included in the selected copyright information. play.

If it turns out that the content is judged to be playable, the copyright management unit 108 outputs the judgment result indicating that the content is playable to the key control unit 104 .

If the content is judged to be unplayable, the copyright management unit 108 outputs a judgment result indicating that the content is unplayable to the key control unit 104 .

If the copyright information group is not extracted, the copyright management unit 108 outputs to the key control unit 104 a judgment result indicating that the content cannot be played.

(7) Remote controller 112, receiving unit 106, driving unit 101, and communication unit 110

(remote control 112)

As shown in FIG. 1 , the remote controller 112 has a package consisting of an upper case and a lower case. In this package, the lower case houses a flat terminal block. At the same time, a plurality of operation buttons are arranged on the upper casing. These action buttons are printed with legends such as activate, confirm, replay, numbers 1 to 12, and move up, down, left, and right.

A plurality of switches that are turned on or off according to user's button operations are arranged on the terminal block at positions corresponding to the operation buttons. In addition, an infrared emitting unit and a conversion circuit are formed on the wiring board.

When the switch is opened or closed as a result of the user's operation on the corresponding button, the switching circuit detects the opening and closing of the switch, generates an electrical signal corresponding to the opening or closing of the switch, converts the electrical signal into a digital signal, and converts the The digital signal is output to the infrared emitting unit. The infrared emitting unit receives the digital signal, and emits or stops the infrared ray according to the digital signal.

By doing so, the remote controller 112 emits infrared rays carrying signals corresponding to user button operations.

(receiving unit 106)

The receiving unit 106 receives infrared rays from the remote controller 112 , extracts signals corresponding to button operations from the infrared rays, and outputs the extracted signals to the playback control unit 102 .

For example, if the extracted signal indicates a playback operation, the receiving unit 106 outputs a playback instruction to the playback control unit 102 .

(communication unit 110)

The communication unit 110 is connected to the license server device 300 via the Internet 10 .

To acquire the copyright, the communication unit 110 establishes an encrypted channel such as SAC (Secret Authentication Channel) with the communication unit 301 in the license server device 300 . In detail, the communication unit 110 shares a session key with the license server device 300 . Then, the communication unit 110 requests copyright transmission from the license server device 300 . In response, the communication unit 110 receives the encrypted copyright information from the communication unit 301 , decrypts the encrypted copyright information with the session key, and writes the decrypted copyright information into the copyright information table 121 of the copyright storage unit 109 .

(drive unit 101)

The drive unit 101 reads information from the recording medium 200 under the control of any one of the playback control unit 102 , decryption unit 103 , key control unit 104 , and media key generation unit 105 . The driving unit 101 outputs the read information to a corresponding unit.

1.4 Configuration of License Server Device 300

FIG. 11 shows the configuration of the license server device 300 . In this figure, a license server device 300 includes a communication unit 301 , a communication control unit 302 , a copyright generation unit 303 , and a control unit 306 . A display unit 304 and an input unit 305 are connected to the license server device 300 .

The license server device 300 is actually realized by a computer system including a microprocessor, ROM, RAM, hard disk unit, communication unit (network adapter), display unit, keyboard, and mouse. Store computer programs on RAM or hard disk units. The microprocessor operates according to the computer program to implement the functions of the constituent elements of the license server device 300 .

The communication unit 301 is connected to the playback device 100 via the Internet 10 . Under the control of the communication control unit 302 , the communication unit 301 establishes an encrypted channel such as SAC with the communication unit 110 in the playback device 100 . In doing so, the communication unit 301 shares the session key with the playback device 100 . After the encrypted channel is established, the communication unit 301 transfers information between the copyright generation unit 303 and the playback device 100 under the control of the communication control unit 302 .

After the encrypted channel is established, the copyright generating unit 303 receives a request for copyright transmission from the playback device 100 through the Internet 10, the communication unit 301, and the communication control unit 302. In response, the copyright generating unit 303 generates copyright information for the playback device 100, encrypts the copyright information using the session key, and transmits the encrypted copyright information to the playback device 100 through the communication control unit 302, the communication unit 301, and the Internet 10.

The input unit 305 receives operations from the operator of the license service apparatus 300 and outputs the received operations to the control unit 306 .

The display unit 304 displays information under the control of the control unit 306 .

1.5 Operation of content playback system 1

The operation of the content playback system 1 is described below.

(1) Content playback start operation

FIG. 12 is a flowchart of the operation of the playback device 100 when content playback starts.

When electric power is received from the power supply unit (S103), a playback operation is received from the remote controller 112 through the receiving unit 106 (S101-S102), or a signal indicating that the insertion of the recording medium 200 is detected from the drive unit 101 is received (S104-S105). ), the playback control unit 102 outputs the content decryption instruction to the decryption unit 103 (S106). The decryption unit 103 outputs a media key acquisition instruction to the key control unit 104 (S107). The key control unit 104 outputs the media key generation instruction to the media key generation unit 105 (S108).

(2) Media key generation operation by the media key generation unit 105

FIG. 13 is a flowchart of a media key generation operation performed by the media key generation unit 105 .

When receiving the media key generation instruction from the key control unit 104 (S108), the media key generation unit 105 reads the device information 141 from the device information storage unit 111 (S121).

Next, the media key generation unit 105 attempts to read a set of media information from the media information table 280 on the recording medium 200 (S122). Since the same device information as the device information 141 is not included in the media information table 280, if all sets of media information have been read from the media information table 280 (S123: YES), the media key generation unit 105 converts the media key to A key generation failure notification is output to the key control unit 104 (S141). The key control unit 104 outputs a media key acquisition failure notification to the decryption unit 103 (S142). The decryption unit 103 outputs a decryption failure notification to the playback control unit 102 (S143). The playback control unit 102 terminates the subsequent content playback operation (S144).

If any group of media information has not been read from the media information table 280 (S123: No), the media key generation unit 105 extracts device information from the read media information (S124), and combines the extracted device information with the device information 141 is compared (S125). If they do not match (S125: NO), the operation returns to step S122.

If they match (S125: YES), the media key generation unit 105 reads the device key 142 from the device information storage unit 111 (S126). The media key generation unit 105 also extracts an encrypted media key from the read media information (S127). The media key generation unit 105 decrypts the encrypted media key with the device key 142 (S128), and outputs the decrypted media key to the key control unit 104 (S129). The key control unit 104 outputs a media key acquisition success notification to the decryption unit 103 (S130). The decryption unit 103 outputs a media key acquisition success notification to the playback control unit 102 (S131).

(3) Content playback control operation by the playback control unit 102

FIG. 14 is a flowchart of a content playback control operation performed by the playback control unit 102 .

When receiving the media key acquisition success notification from the decryption unit 103 ( S131 ), the playback control unit 102 reads playback control information including playback number “1” from the playback path information table 210 . The playback control unit 102 extracts the content name from the read playback control information (S152), and instructs the decryption unit 103 to decrypt and playback the encrypted content identified by the extracted content name (S153). Thereafter, the playback control unit 102 attempts to extract the next playback number from the playback control information (S154). If the playback control information has no next playback number (S155: NO), the playback control unit 102 ends the operation.

If the playback control information contains the next playback number (S155: Yes), the playback control unit 102 reads the playback control information whose playback number matches the extracted next playback number from the playback path information table 210. (S156). The playback control unit 102 extracts the content name from the read playback control information (S157), and inquires of the copyright management unit 108 whether the encrypted content identified by the extracted content name can be played (S158).

If the copyright management unit 108 judges that the content is not playable (S159: NO), the playback control unit 102 extracts an alternative playback number from the read playback control information (S163). Then, the playback control unit 102 reads playback control information whose playback number matches the extracted alternative playback number from the playback path information table 210 (S164), and extracts from the read playback control information Contents name (S165).

The playback control unit 102 instructs the decryption unit 103 to decrypt and play the encrypted content identified by the extracted content name (S160). Then, the playback control unit 102 tries to extract the next playback number from the playback control information (S161). If the playback control information has no next playback number (S162: NO), the playback control unit 102 ends the operation.

If the playback control information contains the next playback number (S162: YES), the playback control unit 102 returns to step S156.

(4) Content decryption and playback operations by decryption unit 103 and playback unit 107

FIG. 15 is a flowchart of content decryption and playback operations performed by the decryption unit 103 and the playback unit 107.

The decryption unit receives a content name and a decryption and playback instruction from the playback control unit 102 (S170). The decryption unit 103 acquires the content key from the key control unit 104 (S171), and reads the encrypted content identified by the received content name from the recording medium 200 (S172).

Next, the decryption unit 103 judges whether the encrypted content includes an encrypted button data table (S173). If the encrypted content does not include the encrypted button data table (S173: NO), the decryption unit 103 decrypts the encrypted content in pack units with the acquired content key, and outputs the decrypted content to the playback unit 107. The playback unit 107 decodes the decrypted content to generate digital video and audio data, and generates analog video and audio signals from the digital video and audio data (S174). The display device 113 outputs the video signal as video, and outputs the audio signal as sound (S175).

If the encrypted content includes the encrypted button data table (S173: YES), the decryption unit 103 decrypts the encrypted button data table using the acquired content key (S181). Then, the decryption unit 103 performs steps S183 to S188 for each set of button data included in the decrypted button data table (S182, S189).

The decryption unit 103 extracts the playback number from the button data (S183). The decryption unit 103 reads the content name (S184) corresponding to the playback number extracted from the playback path information table 210 through the playback control unit 102, and queries the copyright management unit 108 whether the content identified by the file name can be played (S185). If the content is judged to be playable (S186: YES), the decryption unit 103 extracts unselected data and selected data representing normal button display from the button data (S187). If the content is judged not to be playable (S186: No), the decryption unit 103 extracts grayed data representing a grayed-out button display from the button data (S188).

Then, the decryption unit 103 decrypts the encrypted content in units of packets using the content key (S190). The decryption unit 103 outputs the decrypted content to the playback unit 107 . The decryption unit 103 also outputs the selected data and unselected data or grayed out data extracted for each set of button data to the playback unit 107 . The playback unit 107 superimposes selected data and unselected data or grayed out data on the video data to play content in which a plurality of buttons are superimposed. The display device 113 outputs the video signal as video, and outputs the audio signal as sound (S191).

(5) Content key acquisition operation by the key control unit 104

FIG. 16 is a flowchart of a content key acquisition operation performed by the key control unit 104 .

The key control unit 104 receives a content key acquisition instruction and a content name from the decryption unit 103 (S200). The key control unit 104 reads the key control information containing the received content name from the key control information table 260 on the recording medium 200 (S201), and extracts the key generation information (S201) from the read key control information ( S202).

The key control unit 104 judges whether the key generation information is "00" (S203). If the key generation information is "00" (S203: Yes), the key control unit 104 extracts the content information from the key control information (S204), and stores the decrypted media key received from the media key generation unit 105 The key and the extracted content information are concatenated in this order. The key control unit 104 applies a one-way function to the concatenation result to generate a content key (S205), and outputs the content key to the decryption unit 103 (S209).

If the key generation information is not "00" (S203: No), the key control unit 104 acquires the copyright key corresponding to the content identified by the received content name from the copyright management unit 108 (S206). Then, the key control unit 104 judges whether the key generation information is "01" or "10" (S207). If the key generation information is "10" (S207: No), the key control unit 104 outputs the copyright key as the content key to the decryption unit 103 (S209).

If the key generation information is "01" (S207: YES), the key control unit 104 concatenates the decrypted media key and copyright key in this order, and applies a one-way function to the concatenation result to generate a content key ( S208). The key control unit 104 outputs the content key to the decryption unit 103 (S209).

(6) Copyright key acquisition operation performed by the copyright management unit 108

FIG. 17 is a flowchart of a copyright key acquisition operation performed by the copyright management unit 108 .

The copyright management unit 108 receives the content key and copyright mode information from the key control unit 104 (S221). The copyright management unit 108 judges whether the copyright mode information is "00" or any one of "01", "10", and "01, 10" to judge whether any copyright mode is specified (S222).

If the copyright mode is specified, that is, if the copyright mode information is any one of "01", "10" and "01, 10" (S222: No), the copyright management unit 108 tries to obtain the copyright information from the copyright storage unit 109. Copyright information including copyright mode information and content name is extracted from the information table 121 (S223).

If the copyright mode is not specified, that is, if the copyright mode information is "00" (S222: YES), the copyright management unit 108 attempts to extract copyright information including the content name from the copyright information table 121 (S224).

If one or more sets of copyright information are extracted as a result (S225: Yes), the copyright management unit 108 selects one set of copyright information (S226). Then, the copyright management unit 108 judges whether or not the content identified by the content name is playable based on the playback count or playback effective date included in the selected copyright information (S227).

If the content is judged to be playable (S228: Yes), the copyright management unit 108 extracts the copyright key from the copyright information (S229), and outputs the copyright key to the key control unit 104 (S230).

If the content is judged not to be playable (S228: No), or if no copyright information group is extracted (S225: No), the copyright management unit 108 ends the operation.

(7) Playability judging operation by the key control unit 104

FIG. 18 is a flowchart of the playability judging operation performed by the key control unit 104.

The key control unit 104 receives a content name and a playability judgment instruction from the decryption unit 103 (S241). The key control unit 104 reads the key control information containing the received content name from the key control information table 260 on the recording medium 200 (S242), and extracts the key generation information (S242) from the read key control information ( S243).

The key control unit 104 judges whether the key generation information is "00" (S244). If the key generation information is "00" (S244: Yes), the key control unit 104 extracts the playability information from the key control information (S245), and judges whether the playability information is "0" or "1" ( S246). If the playability information is "1" (S246: "1"), the key control unit 104 notifies the decryption unit 103 that the content identified by the content name is playable (S248). If the playability information is "0" (S246: "0"), the key control unit 104 notifies the decryption unit 103 that the content is not playable (S247).

If the key generation information is not "00" (S244: No), the key control unit 104 extracts the playability information from the key control information (S249), and judges whether the playability information is "0" or "1" (S250). If the playability information is "1" (S250: "1"), the key control unit 104 notifies the decryption unit 103 that the content is playable (S251). If the playability information is "0" (S250: "0"), the key control unit 104 extracts the copyright mode information from the key control information (S252), and combines the playability judgment instruction, the copyright mode information, and the content The name is output to the copyright management unit 108 (S253). The copyright management unit 108 judges whether the content can be played (S254). The key control unit 104 receives the judgment result from the copyright management unit 108 (S255), and outputs the judgment result to the decryption unit 103 (S256).

(8) Playability Judgment Operation by Copyright Management Unit 108

FIG. 19 is a flowchart of the playability judging operation performed by the copyright management unit 108. In FIG.

Copyright management unit 108 receives playability judgment instruction, content name and copyright mode information (S253) from key control unit 104, and judges whether copyright mode information is "00" or "01", "10" and "01,10" Any one of " (S261). If the copyright mode information is any one of "01", "10" and "01, 10", that is, if the copyright mode is specified for the content identified by the content name (S261: No), the copyright management unit 108 tries Copyright information including copyright mode information and content name is extracted from the copyright information table 121 of the copyright storage unit 109 (S262). If the copyright mode information is "00", that is, if no copyright mode is specified for the content (S261: YES), the copyright management unit 108 attempts to extract copyright information including the content name from the copyright information table 121 (S263).

If one or more sets of copyright information are extracted as a result (S264: YES), the copyright management unit 108 selects one set of copyright information (S266). Then, the copyright management unit 108 judges whether or not the content is playable based on the playback count or playback effective date included in the selected copyright information (S267). If the content is judged to be playable (S268: Yes), the copyright management unit 108 notifies the key control unit 104 that the content is playable (S269).

If the content is judged to be unplayable (S268: No), the copyright management unit 108 notifies the key control unit 104 that the content is unplayable (S265).

If the copyright information group is not extracted (S264: No), the copyright management unit 108 notifies the key control unit 104 that the content is not playable (S265).

(9) Operation of acquiring copyright information from the license server device 300

FIG. 20 is a flowchart of the operation of acquiring copyright information from the license server device 300. As shown in FIG.

The communication unit 110 in the playback device 100 establishes an encrypted channel, ie, SAC, with the communication unit 301 in the license server device 300 (S301).

Then, the communication unit 110 requests transmission of copyright from the communication unit 301 (S302).

The copyright generating unit 303 in the license server device 300 generates copyright information for the playback device 100 (S303), and encrypts the generated copyright information (S304). The copyright generation unit 303 transmits the encrypted copyright information to the playback device 100 through the communication control unit 302, the communication unit 301, and the Internet 10 (S305).

The communication unit 110 decrypts the encrypted copyright information (S306), and writes the decrypted copyright information into the copyright storage unit 109 (S307).

1.6 Modifications

Although, the present invention has been described by way of the above embodiments, it is obvious that the present invention is not limited to the above. Exemplary modifications are given below.

(1) Although the present invention is not limited thereto, the above-described embodiments describe playback path control based on playback control information and grayed-out button displays, such as two playback options based on license-based content playability. Example of put control. For example, the following modifications (i) to (iii) are possible.

(i) The recording medium 200 can store standard version content that can be used by purchasing the recording medium 200, and director's cut version content that can only be used by purchasing a special copyright separately. In the playback path information table 210 shown in FIG. 3, the next playback number 219 specifies the playback control information corresponding to the director's cut version content, while the alternative playback number 220 specifies the playback control information corresponding to the standard version content. Replay control information.

Meanwhile, the recording medium 200 may store purchase guide contents including pictures for purchasing contents, and commercial advertisement contents including advertisement messages. If the user does not have a license for the content or the playback validity date of the content has expired, the purchase guide content or the commercial content is forcibly played back. At the same time, the operation of acquiring a license from the license server device 300 can be forcibly performed.

Also, if the user does not have a license or the playback validity date has expired, any one of special playback, menu display, angle switching, and stream switching is prohibited.

(ii) Playback control can be applied to angle switching in DVD based on license-based content playability.

More specifically, the recording medium 200 stores angle content of multiple segments whose angles are switched. These angle content pieces are grouped according to replay points. All angle content segments belonging to an angle content group are playable at a playback point, and thus an angle content segment is selected and played back at the playback point. All angle content pieces belonging to another angle content group are playable at another playback point, and thus one angle content piece is selected and played back at that playback point. In the playback path information table 210 shown in FIG. 3, the playback control information corresponding to the angle content may include the next playback number specifying the next angle content to be selected, if it is determined by license conditions or the like. If the angle content specified by the next playback number cannot be played, the playback control information may include an alternative playback number specifying the angle content to be selected.

Here, the playback control information may include a plurality of next playback numbers. The playback control information may also include a plurality of alternative playback numbers corresponding to a plurality of next playback numbers.

Information about the playability of multiple license-based angle content may also be stored. In other words, the data structure of the key control information table 260 in FIG. 8 and the copyright information table 121 in FIG. 10 can also be used for angle switching. In this case, each content name in the key control information table 260 and the copyright information table 121 identifies angle content.

This makes it possible to disable switching to unusable angles.

This modification can be summarized as follows. The angle content of the plurality of angle-switched segments is recorded on the recording medium 200 in advance. The playback control unit 102 in the playback device 100 receives an instruction to play the angled content, and the copyright management unit 108 determines whether the angled content is playable based on the corresponding copyright information in the copyright information table 121 . Based on the judgment result of the copyright management unit 108 , the playback control unit 102 selects the angle content to be played next from the appropriate angle content group on the recording medium 200 . The decryption unit 103 and the playback unit 107 decrypt and play the selected angle content.

(iii) Similarly, playback control based on license-based content playability can be applied to audio/subtitle stream switching. This makes it possible to disable switching to unavailable audio/subtitle streams. The audio/subtitle stream here refers to auxiliary (additional) content that is played back and output together with video content.

The recording medium 200 may store a plurality of auxiliary content pieces grouped according to playback points or playback sections. At one playback point or playback section, all pieces of auxiliary content belonging to one auxiliary content group are playable. For example, English audio data, Japanese audio data, and Chinese audio data all belong to such an auxiliary content group. At a playback point or playback portion, one of these auxiliary content pieces is selected and played back.

At the same time, all auxiliary content segments belonging to another auxiliary content group are playable at another playback point or playback section.

Assume that English audio data, Japanese audio data, and Chinese audio data are recorded on the recording medium 200 corresponding to each piece of content, and that a license permits the use of English audio data and Chinese audio data, but the license does not allow the use of Japanese audio data. In this case, English audio data may be played back instead of Japanese audio data.

Meanwhile, it is assumed that English subtitle data, Japanese subtitle data, and Chinese subtitle data are recorded on the recording medium 200 corresponding to each piece of content, and a license allows only English subtitle data to be used. In this case, English subtitle data may be played back instead of Japanese or Chinese subtitle data.

That is, when the recording medium 200 stores a plurality of pieces of auxiliary content, the playback control information corresponding to the content in the playback path information table 210 includes an auxiliary number for identifying the auxiliary content to be played together with the content, if Where the ancillary content identified by the ancillary number is not playable under license or the like, the playback information includes an alternate ancillary number identifying the ancillary content to be played.

Information about the playability of a plurality of auxiliary contents according to the license may also be stored. In other words, the data structures of the key control information table 260 in FIG. 8 and the copyright information table 121 in FIG. 10 can also be applied to auxiliary content. In this case, each content name in the key control information table 260 and the copyright information table 121 identifies auxiliary content.

This modification can be summarized as follows. A plurality of pieces of auxiliary content such as an audio stream and a subtitle stream are recorded on the recording medium 200 . The playback control unit 102 in the playback device 100 receives an instruction to play auxiliary content. The copyright management unit 108 determines whether the auxiliary content is playable based on the corresponding copyright information in the copyright information table 121 . Based on the judgment result of the copyright management unit 108, the playback control unit 108 selects the auxiliary content to be played next from the appropriate auxiliary content group on the recording medium 200. The decryption unit 103 and playback unit 107 decrypt and playback the selected auxiliary content.

(2) The above embodiment describes the case where the key control information table 260 shown in FIG. 8 is stored on the recording medium 200 in an unencrypted form, but this is not limiting to the present invention. In order to prevent unauthorized playback or copying by falsifying the playability information or copyability information in the key control information table 260, the key control information table 260 may be encrypted or the like. In this case, it is effective to encrypt the key control information table 260 with the media key. Therefore, the playability information and copyability information in the key control information table 260 can be prevented from being falsified.

(3) The above-mentioned embodiment has described an example in which the content recorded on the recording medium 200 is played back, but the same method can be used when copying the content recorded on the recording medium 200 .

That is, when a user requests to copy content recorded on the recording medium 200, the recording device having the same configuration as the playback device 100 acquires the decrypted media key in the same manner as in FIG. 13 . Then, the recording apparatus judges the copyability of the content in the same manner as in FIG. 14, and if judged to be copyable, copies the content to another recording medium.

(4) As a modification to the above-described embodiment, the content recording/playback system 1b is explained as follows.

Fig. 21 shows the configuration of the content recording/playback system 1b. In this figure, a content recording/playback system 1b is roughly composed of a recording/playback device 100b and a license server device 300b connected through the Internet 10. At the same time, the recording medium 200b is also connected to the recording/playback apparatus 100b by the user.

The recording medium 200b stores in advance a medium ID 501 uniquely corresponding to the recording medium 200b.

The license server device 300b stores the key K 521, the content key 531, and the content 532 in advance.

The license server device 300b acquires the medium ID 501 from the recording medium 200b via the recording/playback device 100b and the Internet 10 (S401). The license server device 300b reads the key K521 (S402), and concatenates the medium ID 501 and the key K521 in this order to generate the concatenated key K'522 (S403).

Then, the license server device 300b reads the content key 531, and applies an encryption algorithm to the content key 531 using the concatenated key K'522 to generate the encrypted content key 533 (S404). The license server device 300b writes the encrypted content key 533 as the encrypted content key 511 into the recording medium 200b via the Internet 10 and the recording/playback device 100b (S406). The license server device 300b also reads the content 532, and applies an encryption algorithm to the content 532 using the content key 531 to generate encrypted content 534 (S405). The license server device 300b writes the encrypted content 534 as the encrypted content 512 in the recording medium 200b via the Internet 10 and the recording/playback device 100b (S407).

Thereafter, the recording/playback device 100b reads the medium ID 501 from the recording medium 200b (S421), and acquires the key K521 from the license server device 300b via the Internet 10 (S422). The recording/playback device 100b concatenates the medium ID 501 and the key K 521 in this order to generate a concatenation key K'541 (S423). The recording/playback device 100b reads the encrypted content key 511 from the recording medium 200b (S424), and applies a decryption algorithm to the encrypted content key 511 with the serial key K'541 to generate a decrypted content key 542 (S426) . The recording/playback device 100b also reads the encrypted content 512 from the recording medium 200b (S425), and applies a decryption algorithm to the encrypted content 512 with the decrypted content key 542 to generate the decrypted content 543 (S427). The recording/playback device 100b plays back the decrypted content 543 (S428), and displays the content (S429).

In this content recording/playback system 1b, the recording/playback device 100b writes the encrypted content key 511 and the encrypted content 512 into the recording medium 200b, and reads the encrypted content key from the recording medium 200b. 511 and encrypted content 512. However, the present invention is not limited thereto.

For example, the content recording/playback system 1b may include a recording device and a playback device instead of the recording/playback device 100b. In this case, the recording device writes the encrypted content key and the encrypted content output from the license server device 300b into the recording medium 200b, and the playback device reads the encrypted content key and encrypted content from the recording medium 200b. content, and replays the encrypted content.

(5) The above embodiment describes the case where if the content is judged to be unplayable, the same playback control is performed regardless of why the content is unplayable. This can be modified as follows.

For example, different playback controls may be performed depending on whether the user does not have a license for the content or whether the content's playback validity date has expired. If the user does not have a license, the content indicated by the alternative playback number is played back as in the above-described embodiment. On the other hand, if the playback valid date expires, the original content is played back while displaying a message indicating that the playback valid date has expired, or alternatively displaying playback purchase guide content.

Meanwhile, the playback control information in the playback path information table 210 may also include the next playback number, the first alternative playback number, and the second alternative playback number. As an example, the first alternative replay number specifies the replay control information to use when the user does not have a license, while the second alternative replay number specifies the Specifies the playback control information to use. In this case, if the license allows playback of the content, the playback control unit 102 uses the next playback number, if the user does not have a license, uses the first alternative playback number, and if the playback If the valid date expires, a second, alternate replay number is used.

That is to say, the playback path information table 210 shown in FIG. 3 includes a first alternative playback number and a second alternative playback number, so that the playback control unit 102 selects the content according to why the content cannot be played. Use the appropriate alternate replay number.

The playback control information may also include a third alternative playback number, a fourth alternative playback number, . . . The playback control unit 102 selects an appropriate alternative playback number according to the license conditions.

Meanwhile, the copyright management unit 108, the copyright storage unit 109, and the communication unit 110 in the playback device 100 may be realized by a removable device such as a card. In this case, if the removable device is not connected to the playback device 100, the query to the rights management unit 108 will fail. In this case, different playback controls are possible.

(6) The above embodiments describe the case where only content playability is judged in the content key acquisition operation and the copyright key acquisition operation, but this is not a limitation of the present invention.

For example, the key control information in the key control information table 260 shown in FIG. 8 and the copyright information in the copyright information table 121 shown in FIG. playback quality information for .

Such information can be used in content key acquisition operations and copyright key acquisition information as described below. The key control unit 104 will write the playback quality information included in the copyright information on top of the playback quality information included in the corresponding key control information so that the playback of the former is given priority over the playback quality information of the latter. quality information. The key control unit 104 outputs the written playback quality information to the playback unit 107 through the decryption unit 103, and the playback unit 107 plays back the content with the playback quality indicated by the received playback quality information.

This makes it possible for the playback unit 107 to down-convert content from HD to SD or QCIF (Quarter Common Intermediate Format) and play back the content.

(7) The above embodiment has described the case where the copyright information in the copyright information table 121 shown in FIG. 10 includes the copyright mode information. However, according to this configuration, there is a danger that copyright mode information may be falsified. Different copyright models are usually managed by different companies, and there may be malicious companies performing unauthorized actions against other companies.

This problem can be avoided by digitally signing copyright information including copyright mode information and other data, which appends the generated signature data to the copyright information and other data, and includes them in the signer's certificate.

For example, such a certificate includes the certificate's serial number, copyright information including copyright mode information, a signer's identification code, date of signature, certificate validity date, and signature data. The signature data is generated by digitally signing the serial number, copyright information, identification code, signature date, and expiration date with the signer's private key.

In order to use the copyright information, the playback device 100 obtains the public key of the signer, and verifies the signature data and other data included in the certificate with the obtained public key to judge whether the copyright information has been falsified. The playback device 100 will continue to use the copyright information only if the copyright information has not been tampered with.

Meanwhile, the key control unit 104 and the copyright management unit 108 in the playback device 100 can perform mutual authentication using SAC. If the mutual authentication fails, the key control unit 104 and the copyright management unit 108 terminate subsequent information transmission. If the mutual authentication is successful, the key control unit 104 and the copyright management unit 108 perform subsequent information transmission. Here, each of the key control unit 104 and the copyright management unit 108 may be realized by a discrete, movable module independent of the playback device 100 .

In this case, the key control unit 104 may extract the copyright mode information from the certificate received during the mutual authentication, and check whether the extracted copyright mode information matches the copyright mode information included in the corresponding key control information .

CRL (Certificate Revocation List) indicates information for identifying invalid modules that may be stored in each recording medium 200 and copyright storage unit 109 when mutual authentication is performed. Such a CRL allows each key control unit 104 and rights management unit 108 to avoid invalid modules.

As an alternative method, the key control unit 104 may reserve a first module identifier for identifying an invalid module. In this case, the key control unit 104 acquires an identifier for identifying the copyright management unit 108, and judges whether the acquired identifier matches the first module identifier. If they match, the key control unit 104 refuses information transmission with the copyright management unit 108 .

Meanwhile, the recording medium 200 may store a second module identifier for identifying an invalid module. In this case, the copyright management unit 108 reads the second module identifier from the recording medium 200, acquires an identifier for identifying the key control unit 104, and judges whether the acquired identifier matches the second module identifier match. If they match, the copyright management unit 108 refuses information transmission with the key control unit 104 .

(8) The above embodiment described that if the key control information corresponding to the content includes the key generation information indicating "media key" and the playability information indicating "unplayable", the content is unconditionally judged as unplayable Case. However, the present invention is not limited thereto. Even when the key generation information indicates "media key" and the playability information indicates "unplayable", the key control unit 104 may inquire of the copyright management unit 108 whether the content is playable.

(9) The above embodiment describes the case where the key control information table 260 is stored on the recording medium 200 separately from the encrypted content, but this is not a limitation of the present invention.

For example, key control information may be multiplexed with encrypted content identified by a content name included in the key control information. This clarifies the correspondence between key control information and encrypted content, making it unnecessary to include the content name in the key control information. The playback device 100 can acquire the key control information by separating the key control information from the encrypted content.

Meanwhile, the key control information table 260 may be stored on a recording medium different from the recording medium 200 . Alternatively, the key control information table 260 may be acquired through a network. This is especially effective where not all pieces of content are recorded on one packaged medium, but additional content is fetched separately from the network and recorded on the HDD.

(10) The above embodiment has described the case where the copyright information in the copyright information table 121 shown in FIG. 10 includes a content name indicating a content file name, but the present invention is not limited thereto.

As an example, the copyright information (also referred to as agreement information) includes a copyright identifier (also referred to as a license identifier or agreement identifier) for identifying the copyright information, and the copyright identifier also includes the key shown in FIG. 8 In the corresponding key control information of the control information table 260. Based on the copyright identifier, the copyright management unit 108 searches for the copyright information.

The copyright identifier may also be included in the corresponding playback control information of the playback path information table 210 shown in FIG. 3 . By using the copyright identifier, the playback control unit 102 can query the copyright management unit 108 through the decryption unit 103 and the key control unit 104 whether the content is playable, and use the judgment result of the copyright management unit 108 .

As can be seen from FIG. 3, the playback control information includes a content name, ie, a content identifier for identifying the content. Thus, the recording medium 200 can store a correspondence table of content identifiers and copyright identifiers. The playback control unit 102 extracts the content identifier from the playback control information, reads the copyright identifier corresponding to the extracted content identifier from the correspondence table, and uses the copyright identifier by the decryption unit 103 and the key control unit 104 to query the copyright management unit 108 whether the content is playable.

(11) The above embodiments describe the case of acquiring copyright information from the license server device 300, but the present invention is not limited thereto. For example, the copyright information table 121 may be stored on the recording medium 200 such that the playback device 100 reads the copyright information table 121 from the recording medium 200 . Alternatively, the copyright information table 121 may be stored on another recording medium so that the playback device 100 reads the copyright information table 121 from another recording medium.

(12) The above embodiment has described that the playback control unit 102, the decryption unit 103, the key control unit 104, the media key generation unit 105, and the copyright management unit in the playback device 100 can be obtained by operating the CPU in accordance with a computer program. 108, but this is not a limitation of the invention. For example, each of the playback control unit 102, decryption unit 103, key control unit 104, media key generation unit 105, and copyright management unit 108 can be realized by separate hardware.

(13) As an example of the recording medium 200, the above-mentioned embodiment described the BD. BD has a file system such as UDF (Universal Disk Format), so that information recorded on the recording medium 200 shown in FIG. 2 is typically treated as one or more files in the file system. However, this does not limit the present invention.

For example, the media information table 280 may be stored in a specific area of a BD lead-in area or in a user data area of a BD. Alternatively, the media information table 280 may be stored in a BCA (Block Recording Area). A media key can also be generated as follows. An error intentionally generated for the error detection code is set as the first media key. Meanwhile, the second media key is encrypted with the device information of each playback device, and stored in the media information table 280 written in the lead-in area or the user data area. The media key is calculated by applying a one-way function or the like to the first and second media keys.

Meanwhile, identification information stored in the BCA unique to the recording medium 200 may be used as a media key of the recording medium 200 . Alternatively, identification information unique to the title and stored in the lead-in area or the user data area may be used as the media key of the recording medium 200 . Also, an arbitrary value stored in the user data area can be used as the media key of the recording medium 200 .

Meanwhile, MKB (Media Key Block) stored in the lead-in area or the user data area can be used as information unique to the recording medium 200 .

(14) When the key generation information in the key control information is "10" (copyright key) or "01" (combined key), the above embodiment has described the key control information table 260 shown in FIG. The copyright mode information included in the key control information specifies one or more copyright modes specified for the corresponding content. Meanwhile, if the key generation information is "00" (media key), the copyright mode information does not designate any copyright mode with a value of "00". However, this is not a limitation of the present invention.

As an example, the copyright mode information "00" indicates the copyright mode depending on the recording medium, and the copyright mode information "10" or "01" indicates the copyright mode depending on the license. If the copyright mode information is '00', the playback device 100 generates a content key using the media key. If the copyright mode information is '10' or '01', the playback device 100 generates the content key using the copyright key or the combined key.

(15) The present invention relates to a terminal for playing back a medium in which encrypted content is stored, and availability of the encrypted content is determined based on a license and playback control information of the encrypted content. The terminal includes an availability inquiry unit, a playback control unit, a license key acquisition unit, and a decryption unit. The usability inquiry unit inquires whether the encrypted content is permitted to be used according to the license. The playback control unit controls playback based on the inquiry result of the usability inquiry unit and the playback control information. The license key acquisition unit acquires the license key from the license. The decryption unit decrypts the encrypted content using the license key acquired by the license key acquisition unit.

The present invention also relates to a terminal for playing back a medium storing encrypted content and playback control information of the encrypted content, the availability of which is determined based on a license. The playback control information referred to here includes at least playback path information of the encrypted content. The terminal includes an availability inquiry unit, a playback control unit, a license key acquisition unit, and a decryption unit. The usability inquiry unit inquires whether use of the encrypted content is permitted according to the license. The playback control unit controls the playback path based on the inquiry result of the usability inquiry unit and the playback control information. The license key acquisition unit acquires the license key from the license. The decryption unit decrypts the encrypted content using the license key acquired by the license key acquisition unit.

Here, the playback control information may include a content identifier for identifying encrypted content. By using the content identifier, the usability inquiry unit and/or the license key acquisition unit can perform an inquiry and/or license key acquisition.

Here, the playback control information may include a license identifier for identifying the license. By using this license identifier, the usability inquiry unit and/or the license key acquisition unit can perform an inquiry and/or license key acquisition.

The invention also relates to a method for playing back a medium storing encrypted content and playback control information for the encrypted content, the availability of which is determined based on a license. The method includes an availability query step, a playback control step, a license key acquisition step, and a decryption step. The usability inquiry step inquires whether the encrypted content is permitted to be used according to the license. The playback control step controls playback based on the inquiry result of the availability inquiry step and the playback control information. The license key acquisition step acquires a license key from a license. The decryption step decrypts the encrypted content using the license key obtained by the license key acquisition step.

The invention also relates to a method for playing back a medium storing encrypted content and playback control information for the encrypted content, the availability of which is determined based on a license. The playback control information referred to here includes at least playback path information for encrypted content. The method includes a usability query step, a playback control step, a license key acquisition step and a decryption step. The availability inquiry step inquires whether the encrypted content is allowed to be used according to the license. The playback control step controls the playback path based on the inquiry result of the availability inquiry step and the playback control information. The license key acquisition step acquired the license key from the license. The decryption step decrypts the encrypted content with the license key obtained by the license key acquisition step.

(16) The present invention relates to a terminal for playing back a medium storing encrypted content and a media key unique to the medium. The terminal includes a license acquisition unit, a license key acquisition unit, a key generation unit, and a decryption unit. The license acquisition unit acquires a license including at least a key for decrypting encrypted content. The license key acquisition unit acquires the license key from the license. The key generating unit generates a content key from the media key and the license key. The decryption unit decrypts encrypted content with the content key.

The present invention also relates to a terminal for playing back a medium storing encrypted content and a media key unique to the medium. The terminal includes a license acquisition unit, a license key acquisition unit, a key generation unit, an availability judgment unit, and a decryption unit. The license acquisition unit acquires a license including at least a key for decrypting the encrypted content and usage conditions of the encrypted content. The license key acquisition unit acquires the license key from the license. The key generating unit generates a content key from the media key and the license key. The usability judging unit judges whether to permit use of the encrypted content corresponding to the license based on the usage condition. If the encrypted content is judged to be allowed to be used, the decryption unit decrypts the encrypted content using the content key.

The present invention also relates to a terminal for playing back a medium storing encrypted content, a media key unique to the medium, and process control information. The terminal includes a license acquisition unit, a license key acquisition unit, a key generation unit, a key judgment unit, and a decryption unit. The license acquisition unit acquires a license including at least a key for decrypting encrypted content. The license key acquisition unit acquires the license key from the license. The key generating unit generates a content key from the media key and the license key. The key judging unit judges whether to use the license key or the content key to decrypt the encrypted content based on the processing control information. The decryption unit decrypts the encrypted content using the key determined by the key judgment unit.

Here, the handling control information may include a content identifier for identifying encrypted content, and key type information indicating whether a license key or a content key is to be used.

Here, the handling control information can be multiplexed with encrypted content.

The invention also relates to a method for playing back a medium storing encrypted content and a media key unique to the medium. The method includes a license acquisition step, a license key acquisition step, a key generation step and a decryption step. The license acquisition step acquires a license including at least a key for decrypting encrypted content. The license key acquisition step acquires a license key from a license. The key generating step generates a content key from the media key and the license key. The decryption step decrypts the encrypted content using the content key.

The invention also relates to a method for playing back a medium storing encrypted content and a media key unique to the medium. The method includes a license acquisition step, a license key acquisition step, a key generation step, an availability judgment step and a decryption step. The license acquisition step acquires a license including at least a key for decrypting the encrypted content and usage conditions of the encrypted content. The license key acquisition step acquires a license key from a license. The key generating step generates a content key from the media key and the license key. The usability judging step judges whether to permit use of the encrypted content corresponding to the license based on the usage conditions. If the encrypted content is judged to be allowed to be used, the decryption step decrypts the encrypted content using the content key.

The present invention also relates to a method for playing back a medium storing encrypted content, a media key unique to the medium, and process control information. The method includes a license acquisition step, a license key acquisition step, a key generation step, a key judgment step and a decryption step. The license acquisition step acquires a license including at least a key for decrypting encrypted content. The license key acquisition step acquires a license key from a license. The key generating step generates a content key from the media key and the license key. The key judging step judges whether to use the media key or the content key to decrypt the encrypted content based on the processing control information. The decryption step decrypts the encrypted content using the key determined by the key judgment step.

(17) The present invention relates to a terminal for playing back a medium storing encrypted content and a media key unique to the medium. The terminal includes a license acquisition unit, a content key acquisition unit, a key selection unit, and a decryption unit. The license acquisition unit acquires a license including at least a key for decrypting encrypted content. The content key acquisition unit acquires the content key from the license. The key selection unit selects one of the media key and the content key for decrypting the encrypted content. The decryption unit decrypts the encrypted content with the key selected by the key selection unit.

The present invention also relates to a terminal for playing back a medium storing encrypted content, a media key unique to the medium, and key selection information. The terminal includes a license acquisition unit, a content key acquisition unit, a key selection unit, and a decryption unit. The license acquisition unit acquires a license including at least a key for decrypting encrypted content. The content key acquisition unit acquires the content key from the license. The key selection unit selects one of the media key and the content key for decrypting the encrypted content based on the key selection information. The decryption unit decrypts the encrypted content with the key selected by the key selection unit.

The present invention also relates to a terminal for playing back a medium storing encrypted content, a media key unique to the medium, and key selection information. The terminal includes a license acquisition unit, a content key acquisition unit, a key selection unit, an availability judgment unit, and a decryption unit. The license acquisition unit acquires a license including at least a key for decrypting the encrypted content and usage conditions of the encrypted content. The content key acquisition unit acquires the content key from the license. The key selection unit selects one of the media key and the content key for decrypting the encrypted content based on the key selection information. The usability judging unit judges whether to permit use of the encrypted content corresponding to the license based on the usage condition. If it is determined that use of the encrypted content is permitted, the decryption unit decrypts the encrypted content with the key selected by the key selection unit.

Here, the key selection information may include a content identifier for identifying encrypted content and key type information indicating whether a media key or a content key is used.

Here, key selection information can be multiplexed with encrypted content.

Here, the key selection information may include a license identifier for identifying a license corresponding to the encrypted content, so that the content key acquisition unit can acquire the content key from the license identified by the license identifier.

The invention also relates to a method for playing back a medium storing encrypted content and a media key unique to that medium. The method includes a license acquisition step, a content key acquisition step, a key selection step, and a decryption step. The license acquisition step acquires a license including at least a key for decrypting encrypted content. The content key acquisition step acquires the content key from the license. The key selection step selects one of the media key and the content key for decrypting the encrypted content. The decryption step decrypts the encrypted content with the key selected by the key selection step.

The invention also relates to a method for playing back a medium storing encrypted content, a media key unique to that medium, and key selection information. The method includes a license acquisition step, a content key acquisition step, a key selection step, and a decryption step. The license acquisition step acquires a license including at least a key for decrypting encrypted content. The content key acquisition step acquires the content key from the license. The key selection step selects one of the media key and the content key for decrypting the encrypted content based on the key selection information. The decryption step decrypts the encrypted content using the key selected by the key selection step.

The invention also relates to a method for playing back a medium storing encrypted content, a media key unique to that medium, and key selection information. The method includes a license acquisition step, a content key acquisition step, a key selection step, an availability judgment step, and a decryption step. The license acquiring step acquires a license including at least a key for decrypting the encrypted content and usage conditions of the encrypted content. The content key acquisition step acquires the content key from the license. The key selection step selects one of the media key and the content key for decrypting the encrypted content based on the key selection information. The usability judging step judges whether to permit use of the encrypted content corresponding to the license based on the usage conditions. If it is judged that use of the encrypted content is permitted, the decrypting step decrypts the encrypted content using the key selected by the key selecting step.

The invention also relates to media storing encrypted content. The medium also stores a media key unique to the medium and key selection information indicating whether encrypted content is generated by encryption using the media key.

Here, the key selection information may include a content identifier for identifying encrypted content.

Here, the key selection information may include a license identifier for identifying a license of the encrypted content.

(18) The above embodiments have described the case where one key control information table is stored on the recording medium 200 . However, a plurality of key control information tables may be stored on the recording medium 200 .

If the recording medium 200 is a re-recordable or re-writable medium, the user can add encrypted content on the recording medium 200 he or she obtains. When adding encrypted content, it is also necessary to store a key control information table corresponding to the added content.

In this case, the key control unit 104 searches a plurality of key control information tables on the recording medium 200 for a key control information table specifying encrypted content to be judged as playable or unplayable. Here, there may be more than one key control information table specifying encrypted content. In this case, the key control unit 104 detects the key control information table to be referred to based on such a principle that the last stored key control information table is given priority.

In addition, it is also possible to distribute combined content on a plurality of recording media. Especially when the recording medium 200 is a non-recordable medium, the encrypted content added later needs to be recorded on another recording medium. A typical example of other recording media is an HDD mounted on the playback device 100 . The playback device 100 records the added encrypted content on the HDD. In this case, the key control unit 104 searches a plurality of key control information tables on a plurality of recording media storing different parts of the combined content related to each other by linking to find a key control information table to be referred to.

(19) The constituent elements of each device described above may be partially or completely realized by a single system LSI. The system LSI is an ultra-multifunctional LSI produced by integrating a plurality of components on a single chip, and the system LSI is actually realized by a computer system including a microprocessor, ROM, and RAM. Computer programs are stored in RAM. The functions of the system LSI can be realized by a microprocessor operating in accordance with a computer program.

(20) The structural elements of each of the above devices may be partially or completely realized by removable IC cards or discrete modules. The IC card or discrete module referred to here is a computer system including a microprocessor, ROM and RAM. The IC card or module may include the aforementioned ultra-multifunctional LSI. The functions of the IC card or the module can be realized by the operation of the microprocessor according to the computer program. Here, the IC card or module may be tamper-resistant.

(21) Each of the above devices is actually a computer system including a microprocessor, ROM and RAM. Computer programs are stored on RAM. The function of each device can be realized by the microprocessor operating in accordance with this computer program. The computer program is composed of sets of computer instruction codes in order to realize predetermined functions.

(22) The present invention is also applied to the method described above. This method can be realized by executing a program by a computer. Such computer programs may be distributed as digital signals.

The present invention can be realized by computer-readable storage medium such as floppy disk (flexible disk), hard disk, CD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD or semiconductor memory, and above-mentioned computer program or digital signal are recorded in on these media. On the contrary, the present invention can also be realized by computer programs or digital signals recorded on such storage media.

The computer program or digital signal implementing the present invention can also be transmitted through such as an electronic communication network, a wired or wireless communication network, or the Internet, or through data broadcasting.

The invention can also be implemented by a computer system including a microprocessor and a memory. In this case, a computer program may be stored in the memory, and the microprocessor operates in accordance with the computer program.

The computer program or digital signal can be provided to an independent computer system by distributing a storage medium on which the computer program or digital signal is recorded, or transmitting the computer program or digital signal through a network. Then, the stand-alone computer system can execute the computer programs or digital signals to realize the functions of the present invention.

(23) The above-described embodiments and modifications can be freely combined.

(24) A playback device and a playback method for encrypted content and recording media related to the present invention are suitable for content playback of media containing traditional copy-protected content and DRM content, so they are used in media such as packaged media and content distribution It is useful in the field of the recording medium on which the data used by the above playback device and playback method is stored.

Industrial applicability

These devices and the recording medium related to the present invention can be repeatedly and continuously used in the content distribution industry for producing or distributing content. Moreover, the devices involved in the present invention can also be repeatedly and continuously manufactured and sold in the electronic product manufacturing industry.

Claims (13)

1. the content that is used for the combined arrangement of service recorder on recording medium is used equipment, and described combined arrangement comprises many contents, and described content use equipment comprises:

Acquiring unit is used to obtain the appointment to one of many contents;

Judging unit is used for judging based on the protocol information relevant with the use of described given content whether described given content is available;

Selected cell is used for selecting one of described many contents according to the judged result of described judging unit; And

Output unit is used to export selected content;

Wherein, described judging unit obtains described protocol information, and judges based on the protocol information that is obtained whether the content of described appointment is available.

2. content according to claim 1 is used equipment, wherein

Be recorded in the replaceable content designator that described combined arrangement on the described recording medium comprises the content designator of the content that corresponds to each other, be used to identify described appointment and is used to identify described interchangeable content,

If the content of described appointment is determined to be available, described selected cell is by extracting the content that described content designator is selected described appointment from described combined arrangement, if it is unavailable that the content of described appointment is judged as, then described selected cell is selected interchangeable content by extracting corresponding to the replaceable content designator of described content designator from described combined arrangement, and

Described output unit reads the content that is identified by content designator that extracts or replaceable content designator from recording medium, and with described content output of reading.

3. content according to claim 1 is used equipment, wherein

The described combined arrangement that is recorded on the described recording medium comprises the license identifier that is used to identify described protocol information, and

Described judging unit comprises:

The protocol information storage unit, the license identifier and the protocol information that are used to prestore and correspond to each other;

The identifier extraction unit is used for extracting described license identifier from described combined arrangement; And

Judging unit is used for reading protocol information corresponding to the license identifier of being extracted from described protocol information storage unit, and judges based on the protocol information that is read whether the content of described appointment is available.

4. content according to claim 1 is used equipment, wherein

Be recorded in described combined arrangement on the described recording medium comprise correspond to each other, be used to the license identifier that identifies the content designator of described given content and be used to identify described protocol information, and

Described judging unit comprises:

The protocol information storage unit, the described license identifier and the described protocol information that are used to prestore and correspond to each other;

The identifier extraction unit is used for extracting and the corresponding described license identifier of content designator that is used to identify described given content from described combined arrangement; And

Judging unit is used for reading and the corresponding protocol information of license identifier that is extracted from described protocol information storage unit, and judges based on the protocol information that is read whether the content of described appointment is available.

5. content according to claim 1 is used equipment, wherein

The described combined arrangement that is recorded on the described recording medium comprises the content designator that is used to identify described given content, and

Described judging unit comprises:

The protocol information storage unit, the described content designator and the described protocol information that are used to prestore and correspond to each other;

The identifier extraction unit is used for extracting described content designator from described combined arrangement; And

Judging unit is used for reading and the corresponding protocol information of content designator that is extracted from described protocol information storage unit, and judges based on the protocol information that is read whether the content of described appointment is available.

6. content according to claim 1 is used equipment, wherein

The described combined arrangement that is recorded on the described recording medium comprises the playback path information of representing described given content and being close to the corresponding relation between the previous content of exporting before the described given content, and

Described output unit is exported after the described previous content, and described acquiring unit extracts described playback path information from described combined arrangement, and the corresponding appointment of playback path information of obtaining and being extracted.

7. content according to claim 1 is used equipment, wherein

Described many contents comprise many angular content that are used for the multi-angle switching,

Described acquiring unit obtains the appointment to one of described many angular content,

Described judging unit judges based on described protocol information whether the angular content of described appointment is available, and

Described selected cell is selected one group of exportable angular content according to the judged result of described judging unit, and selects an angular content in selected group, and

Described output unit is exported selected angular content.

8. content according to claim 1 is used equipment, wherein

Described many contents comprise many auxiliary contents and constitute the described combined arrangement be recorded on the described recording medium, and every auxiliary content in described many auxiliary contents all comprises the voice data exported with video data and the arbitrary data in the caption data,

Described acquiring unit obtains the appointment to one of described many auxiliary contents,

Described judging unit judges based on described protocol information whether the auxiliary content of described appointment is available,

Described selected cell is selected one group of exportable auxiliary content according to the judged result of described judging unit, and selects an auxiliary content from selected group, and

Described output unit is exported selected auxiliary content.

9. content according to claim 1 is used equipment, wherein

Every copyright that all comprises encryption of described many contents, and

Described output unit is decrypted the enciphered digital works that are included in the selected content, and with the copyright output of being deciphered.

10. a content using method is used in the content use equipment of the combined arrangement of service recorder on recording medium, and described combined arrangement comprises many contents, and described content using method comprises the steps:

Obtain appointment to one of described many contents;

Judge based on the protocol information relevant whether the content of described appointment is available with the use of the content of described appointment;

According to the judged result of described determining step, select one of described many contents; And

Export selected content; Wherein

Described determining step obtains described protocol information, and judges based on the protocol information that is obtained whether the content of described appointment is available.

11. content using method according to claim 10, wherein, described method is realized by computer program.

12. content using method according to claim 11, wherein, described computer program is stored in the computer-readable recording medium.

13. content using method according to claim 11, wherein, described computer program passes through carrier-wave transmission.

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